(1) Field of the Invention
The invention relates to a control or regulating device for electrically controlled valves in hydraulic control apparatus, particularly for relief valves in hydraulic control apparatus for injection molding machines whereby a regulating signal is transmitted to the actuator of the respective electrically controllable valve.
Generally, the control and regulating devices for electrically controllable valves in hydraulic control apparatus are constucted as a control center which transmits the regulating signals to these controllable valves. These control and regulating devices are generally at the same voltage level, i.e., they are voltaically coupled. If interference signals are triggered when addressing the electrically controllable valves, they interfere with the control or regulation due to the voltage coupling which can lead to malfunctions.
(2) Description of Related Art
Similar problems also appear in other areas of the technology, for example in the analogous communications technology. In that technology it is known to insert buffer amplifiers to obtain the voltage decoupling. In digital signal communication it is also known to use optical coupling, for example in digital signal transmission.
It is correspondingly also known to use optical couplers in digital control or regulating devices for hydraulic control apparatus in injection molding machines for addressing and controlling the directional valves. This type of digital control or regulating device for the hydraulic control of injection molding machines has to be initially designed for these optical couplers.